Heating Air By Compression

Purpose

To demonstrate heating air by compression.
 

Equipment

Basketball with hand pump and needle.

 

Images

i5-21

Description

A few pumps of the tire pump into a mostly filled basketball warms the end of the pump noticeably. You can show that this is not due to friction by moving the pump handle back and forth in the same style with no load. You can simultaneously demonstrate cooling by expansion by observing that while the pump and the needle get rather warm, the air inside the ball actually cools.